This invention relates to knowledge base systems.
In such systems, prestored rules and facts form a knowledge base from which useful inferences and conclusions may be drawn by an inference engine.
Commercially available knowledge base system shells include such an inference engine together with facilities that aid the system developer in defining the rules and facts for a given application, and an interface that enables a user to query the system from an interactive terminal.
Some of the facts required for a given application may be available in an already established data base; and the knowledge base system may need to use those facts in responding to a query.
Information is stored and retrieved in data bases typically via a query language such as SQL (structured query language) which, for example, can be used to specify criteria for searching the data base to locate a desired fact.